Pattern of brain glucose utilization following magnetic stimulation

The 2-deoxy-D-(14C) glucose technique was used for autoradiographic mapping of the local cerebral glucose utilization in pigeons which were exposed to a periodically inverted artificial magnetic field in the Earth's field range. Stimulation during daytime resulted in increased values particularly in primary or secondary visual structures. Stimulation during nighttime resulted in increased values in the optic tectum and within the nucleus isthmi. In both situations decreased values were determined in the hypothalamus and increased values in the pineal gland. The results support the concept that magnetic information is transduced by magnetoreceptors and is relayed to structures of the visual system. Moreover, it is suggested, that magnetic stimulation exerts suppressive metabolic effects on the basal hypothalamus.